Clamping and tightening device for blankets and flexible printing plates

ABSTRACT

Device for clamping and tightening of a printing blanket on an impression cylinder and/or a flexible printing plate on a plate cylinder of a printing machine. A cam-shaped clamping rod under spring pressure for one edge of the blanket and/or the flexible plate and a separate tightening rod on which the other end of the blanket and/or the flexible plate is wound. The cam-shaped clamping rod is also designed for a clamping force which increases under the influence of the centrifugal forces with increasing speed of the printing machine.

United States Patent [72] Inventor James McIntyre Ferguson Teaneck, NJ. [2l] Appl. No. 741,584 [22] Filed July 1,1968 [45] Patented Feb. 16, 1971 [73] Assignee Wood Industries, Inc.

Plainfield, NJ.

[54] CLAMPING AND TIGHTENING DEVICE FOR BLANKETS AND FLEXIBLE PRINTING PLATES 1 Claim, 5 Drawing Figs.

[52] U.S. Cl l01/415.1, 101/378 [51] Int. Cl. B41! 1/28, B41f 21/00 [50] FieldofSearch lOl/4l5.1, 378, 246; 100/269, 392

[5 6] References Cited UNITED STATES PATENTS 629,933 8/1899 Spalckhaver l0l/4l5.l

2,186,764 1/1940 Meisel 101/415.1 2,309,161 1/1943 Bre man et al 101/415.1 2,329,830 9/1943 Crafts..... 101/415.1 2,946,282 7/1960 Harless l01/4I5.l

Primary Examiner-William B. Penn Assistant ExaminerE. M. Coven Attorney-Pennie, Edmonds, Morton, Taylor & Adams CLAMPIN G AND TIGHTENING DEVICE FOR BLANKETS AND FLEXIBLE PRINTING PLATES BACKGROUND OF THE INVENTION The invention relates to impression and plate cylinders of printing machines and particularly to the printing blanketclamping devices on the impression cylinders and/or to the clamping devices for thin, flexible printing plate on the plate cylinders. Y

The conventional devices for fastening of the printing blan' kets on the impression cylinders comprise means for hooking one edge of the blanket on pins or .reinforcing this edge by bars or rods and securing these bars or rods in a groove which is cut in the impression cylinder for this purpose, and a socalled reel rod on which the other end of the blanket is wound for tightening it. There are also devices for fastening and tightening of the blanket by using only one reel rod on which both edges of the blanket are simultaneously wound. All of these devices have left something to be desired, particularly with respect to ease of preparing the blanket for being attached to the cylinder, or to ease of handling or to tightening of the blanket evenly over the entire width of the cylinder to keep the blanket in an appropriately taut condition, especially while the printing machine is running. Similarly, thin flexible printing plates such as the so-called wraparound plates or printing plates made of rubber or plastic which are mounted on thin flexible bases have to be fastened on the plate cylin' ders of the printing machines. Various methods and means have been used for this operation such as glueing or attaching rods to the longitudinal edges, bending and crimping of the edges or punching holes along the edges for hooking the plates on the plate cylinder body. All these mentioned methods and means are not very satisfactory for various operating conditrons.

The foregoing problems are solved by this invention:

SUMMARY The invention consists in such novel features, construction arrangements, combinations of parts and improvements as may be shown and described in connection with the apparatus herein disclosed by way of exampleonly and as illustrative of a preferred embodiment. Basically the inventive idea is to separate the function of clamping of one edge of a flexible printing element (blanket and/or flexible printing plate) on a printing machine cylinder (impression cylinderor the plate cylinder), and of tightening the other edge, and of keeping the blanket and/or plate automatically all the time in the taut condition which is essential for good printing. Objects and advantages of the invention will be set forth in part hereafter and in part will be obvious therefrom or may be learned by practicing the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims. 7

The general object of this invention is to provide novel, improved means for clamping and tightening of a printing blanket on an impression cylinder and/or a flexible printing plate on a plate cylinder of a printing machine.

It is another object of the invention to provide contrivances for separate mechanisms for clamping of the blanket and/or the flexible plate and holding it, and for tightening the same.

Yet another object of the invention is to provide a novel mechanism for keeping the blanket and/or the flexible plate taut while the printing machine is running.

A further object of the invention is to provide means for mounting a printing blanket on an impression cylinder and/or a flexible printing plate on a plate cylinder, which does not necessitate special clamping preparations and attachments on the blanket or on the flexible plate prior to mounting it on the cylinder.

Furthermore it is an object of the invention to provide improved and simplified blanket and/or flexible plate clamping and tightening means for easier and faster work resulting in a time saving during the downtime of the'printing machine.

Various further and more specific purposes, features and advantages will clearly appear from the detailed description given below in connection with the accompanying drawing which forms part of the specification and illustrates merely by way of example one embodiment of the device of the invention.

BRIEEDESCRIPTION OF THE DRAWING The following description and in the claims parts will be identified by specific names for convenience, but such names are intended to be as generic in their application to similar parts as the art will permit. Like reference characters denote like parts in the several figures of the drawing, in which:

FIG. 1 is a plan view of one end of a printing machine cylinder, partly broken away;

FIG. 2 is a vertical side view of the end of the printing machine cylinder shown in FIG. 1, partially broken away and sectioned along the line 2-2 in FIG. 5;

FIG. 3 is a cross section of theprinting machine cylinder, taken along the line 3-3 in FIG. 1, partly broken away;

FIG. 4 is an axial end view of the printing machine cylinder;

FIG. 5 is a view of a cross section of the printing machine cylinder, taken along the line 5-5 in FIG. 2, partly broken away.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in more detail to the drawing illustrating a preferred embodiment by which the invention may be realized, there is shown in FIGS. 1 and Zone end of a printing machine cylinder body 11 which has a bearer ring 12 permanently attached thereto. A bearer ring 12 is located at each end of cylinder body 11 for assuring atrue rolling of an impression cylinder with the corresponding plate cylinder which has the identical bearer rings secured thereon at the cor responding location (not shown in the drawing). Bearer ring 12 is made of a hardened special steel and no holes are permitted to be drilled through it. Cylinder body 11 has at least one groove 13 (but may have more) which has a narrow open ing at the surface of cylinder body 11 but has inwardly slanting walls 14 ending in the cavity 15 which is wide enough for accommodating the fastening reel rods 16 and 17 for the blanket 18 or for a flexible plate, as the case may be. Since the fastening reel rods have to be located at a conveniently short distance from the cylinder surface, and since no gap between cylinder body 11 and bearer ring 12 can be permitted wide enough for locating an operable mechanism for the reel rods therein it is necessary to provide mechanisms by which reel rods 16 and 17 are operated from the ends of cylinder 11 without going through bearer rings 12 but rather extending underneath the latter to the outside.

As shown in FIGS. 1 and 2, the cylinder body 11, generally, comes up against bearer ring 12 which fits the reduced cylinder end 11a and is flush with the outer end thereof. The hub 11b projects out from the reduced end but may carry a barring ring 11c (FIG. 2) which has a diameter only slightly less than that of the reduced cylinder 11a or inside diameter of the bearer ring 12. The inner face F of the machine frame is positioned close to the cylinder end and the bearing seals come still closer to the cylinder ends and may have a diameter intermediate between that of the reduced cylinder end 110 and that of the bearer ring 12. Bearing in mind that the bearer ring must not be bored or cut into, it is apparent that the space available for locating the blanket or plate-operating mechanism is extremely cramped.

To this end a cavity 19 is milled at the end of cylinder body 11 and accommodates a support plate 20. Plate 20 is secured to the cylinder body and located thereon by bolts and screws 20. Reel rods 16 and-17 are journaledl in plate 20, and small gears 21 and 22 are fastened to the ends of reel rods 16 and 17, respectively, by means of screws 21 and 22', the heads of which are flush with the faces of the gears 21 and 22. The teeth of gear 21 are partially cut away, on one side to provide clearance with the teeth of gear 22, and on the other for providing a cutout 23. A pin 24 is positioned in plate 20, and cooperates with cutout 23 to limit the rotation of gear 21 (FIG. 5).

Gears 21 and 22 mesh with gears 25, 26 respectively, which are integral with short shafts 27, 28. A block 29 is fitted into a cutout 30 in the reduced end of the cylinder body which seats bearer ring 12 and is secured in place by bolts 29. Shafts 27, 28 are rotatably located in block 29 and extend through bores in bracket plate 31, which is secured to block 29 by bolts 31. Lever arm 32 is secured to shaft 27 and can be prevented from moving counterclockwise by a pawl 33 which can be swung into and out of holding position about a pivot stud 34. ln the positions of FIG. 4, with the pawl engaged, the reel rod 16 is held in position to open a space between cam surface 46 and adjacent slanted surface 14, for permitting insertion of a blanket (or plate) end. On the other side of lever arm 32 opposite the step 35 where pawl 33 engages lever arm 32, is a plunger 36, which is slidably held in a housing 37 and which is forced by a compression spring 38 against lever arm 32. An adjustment screw plug 39 is provided for modifying the tension of spring 38. Thus, upon unlocking pawl 33, spring 38 forces lever arm 32 by plunger 36 to rotate counterclockwise, which in turn rotates reel rod 16 by gears 25, 23 in the clockwise direction whereby the edge of blanket or flexible plate 18 is .lamped against slanting wall 14. Pin 24 merely prevents the mechanism from overriding in the case that pawl 33 had been unlocked inadvertently when no blanket had been inserted.

A ratchet wheel 40 is attached to the protruding end of shaft 28 and a pawl is swingable located on a pivot stud 42, engaging ratchet wheel 40 for holding shaft 28 in a desired angular position. Shafts 27, 28 have free ends 43, 44, respectively, protruding beyond lever arm 32 and ratchet wheel 40, which are square so that the shafts can be operated by a wrench (not shown in the drawing).

Reel rod 16 is arranged for clamping the leading edge of blanket or flexible plate 18. It has a cam-shaped side 45 which will engage in a wedging manner the edge of blanket or flexible plate 18 by way of the properly curved contour 46 of cam 45. Obviously, the more shaft 16 is rotated in the clockwise direction, the tighter blanket or flexible plate 18 will be held. Since cam 45 extends over the entire length of shaft 16 and thus over the entire width of blanket or flexible plate 18, the latter will be held in place without distortion and/or wrinkles.

After the first edge of blanket or flexible plate 18 has been properly clamped in place, it is wrapped around cylinder body 11 and its other edge is tucked into the slot 47 of reel rod 17, whereupon it is rolled up tightly on the latter. No other preparation of blanket or flexible plate 18 prior to being put on the corresponding printing machine cylinder is required than to cut the two transverse edges of the blanket or plate straight across and at right angles to the longitudinal (circumferential) edges thereof.

The structure of reel rod 16 and cam-shaped side 45 is such that the center of gravity is outside of the center of rod 16 and over to the side of cam 45. When the printing machine is running, the centrifugal force acting on reel rod 16 therefore has the tendency to rotate rod 16 clockwise and it is obvious that the force with which cam contour. 46 presses against the longitudinal edge of blanket or flexible plate 18, increases with the speed of the printing machine and adds to the holding force of spring 38.

While the invention has been described and illustrated with respect to a certain preferred example which gives satisfactory results, it will be understood by those skilled in the art after understanding the principle of the invention, that various other changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore in the appended claims to cover all such changes and modifications.

lclaim:

1. A printing machine cylinderadapted to receive at least one flexible printing element with axially extending edges, said cylindenhaving at least one axially extendin cavity therein, said cavity having a substantially narrow slo opening m the surface of said cylinder and having inwardly diverging slanting walls, said cylinder having hardened steel bearer rings at each end thereof, having first means in said cavity for clamping and holding one of said axially extending edges of said printing element against one of said inwardly slanting walls, second means in said cavity for tightening the other one of said axially extending edges of said element, both said first and said second means disposed for axially extending only between said bearer rings, mechanisms on both said first and second means for the operation thereof from the outside of said bearer rings, third means extending from the inside to the outside of said bearer rings below the latter avoiding penetrating therethrough for said operation of said first and second means, said mechanism having gears on both said first and second means, said means consisting of first and second shafts extending between said bearer rings to the outside thereof, gears on said first and second shafts, said gears on said shafts meshing with said gears on said first and second means, respectively, and operable means attached to the ends of said shafts, said operable means on said end of said first shaft comprising a lever arm, a movable pawl engaging one side of said lever arm in the operated position of said first shaft, a plunger having a spring pressing against the other side of said lever arm, a screwplug arranged for adjusting the force of said spring, the action of said plunger causing said first means to clamp said edge of said flexible element on said slanting wall. 

1. A printing machine cylinder adapted to receive at least one flexible printing element with axially extending edges, said cylinder having at least one axially extending cavity therein, said cavity having a substantially narrow slot opening in the surface of said cylinder and having inwardly diverging slanting walls, said cylinder having hardened steel bearer rings at each end thereof, having first means in said cavity for clamping and holding one of said axially extending edges of said printing element against one of said inwardly slanting walls, second means in said cavity for tightening the other one of said axially extending edges of said element, both said first and said second means disposed for axially extending only between said bearer rings, mechanisms on both said first and second means for the operation thereof from the outside of said bearer rings, third means extending from the inside to the outside of said bearer rings below the latter avoiding penetrating therethrough for said operation of said first and second means, said mechanism having gears on both said first and second means, said means consisting of first and second shafts extending between said bearer rings to the outside thereof, gears on said first and second shafts, said gears on said shafts meshing with said gears on said first and second means, respectively, and operable means attached to the ends of said shafts, said operable means on said end of said first shaft comprising a lever arm, a movable pawl engaging one side of said lever arm in the operated position of said first shaft, a plunger having a spring pressing against the other side of said lever arm, a screwplug arranged for adjusting the force of said spring, the action of said plunger causing said first means to clamp said edge of said flexible element on said slanting wall. 